If you fish Items out of the water using the fishing rod the enchanted book won't have an enchantment on it. I don't know if it also applies to bows.
MC-84796
Minecraft Fishing Bug
Resolved
Duplicate
0
Thank you for your report.
However, your ticket has been resolved as a duplicate.
This issue has been linked to the original bugreport: MC-83897. You can find or add further information on that report.
Please search before reporting any bugs, as it's likely that one exists already.